Metal-enhanced fluorescence of interlaminar composite film with self-assembled quantum Dots/Au@Si02 microarchitecture

摘要

Quantum dots fluorescence-enhanced films, which mainly consisted of CdSe@ZnS quantum dots and noble metal nanoparticles or nanorods, were formed by layer-by-layer self-assembly techniques. This particular architecture consisting of metal nanoparticles-poly (diallyl dimethylammonium chloride) (PDDA)-QDs was characterized by those fabrication processes mainly including surface-modifying the oleic acid-capped CdSe@ZnS QDs (high quantum yield of —89%) with mercaptopropionic acid (MPA) to be charged negatively (-COO-) for following solution-processed assembly, adjusting the size and coating the gold nanoparticlesanorods with silica to form suitable dielectric insulation layer and further optimize the fluorescence-enhanced performance, as well as using the cationic polyelectrolyte to control the charges between layers and form opposite charges between two adjacent layers. After optimizing the structure of the quantum dot fluorescence-enhanced films and corresponding surface plasmon enhancement effect, the enhancement factor of 10.8 in Au NPs@SiO_2-PDDA-QDs complex film and that of 24.7 in Au NRs@SiO_2-PDDA-QDs complex film as compared with the pure quantum dot fluorescence film were achieved, respectively. This indicated that the Au NRs@SiO_2-PDDA-QDs complex film was one of the most promising potentials for further display backlight and biometric identifier application.